A system for controlling a traffic warning triangle to avoid obstacles when moving towards a placement location includes a depth calculating module, a determining module, and a control module. The traffic warning triangle includes a binocular camera to capture real-time images of a path or road in front of the triangle. The depth calculating module compares and analyzes first and second images, captured at the same time, to calculate depth information between the binocular camera and an obstacle. The determining module determines whether the depth information is less than a threshold value. The control module adjusts a moving direction of the mobile warning triangle to avoid the obstacle in response to the depth information being less than the threshold value, according to a process. An obstacle avoidance method of the mobile warning triangle is also provided.